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Class 9 Physics Chapter 8


Updated: 29 Oct 2023

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Class 9 Physics Chapter 8 is about “Thermal Properties of Matter“. This article includes topics such as Thermal Properties of Matter, Temperature, Heat, Measurement of Temperature, Thermometric Property, Temperature Scales, Centigrade or Celsius Scale, Fahrenheit Scale, Kelvin or Absolute Scale, Relationship between Different Scales of Temperature, Conversion between Centigrade and Fahrenheit Scale, Conversion between Centigrade and Kelvin Scale, Thermal Expansion, Thermal Expansion of Solids (Linear Thermal Expansion of Solids, Volume (Cubical) Thermal Expansion of Solids), Thermal Expansion of Liquids, Real Expansion of Liquids, Apparent Expansion of Liquids, Coefficient of Real Expansion, Coefficient of Apparent Expansion, Anomalous Expansion of Water, Applications and Consequences of Thermal Expansion (Railway lines, Opening of Tight Jar Lid, Transmission Lines, Shrink-fitting of Axles into Gear Wheels, Expand Fitting Iron Ring to a Cart Wheel, Expansion Joints, Bimetallic Strip), Heat Capacity and Specific Heat Capacity, Heat Capacity (Thermal Capacity), Specific Heat Capacity (Specific Heat), Importance of High Specific Heat Capacity of Water (Moderate Climate of Sea Shore, As a coolant), Latent Heat and Phase Change, Latent Heat of Fusion, Specific Latent Heat of Fusion, Latent Heat of Vaporization, Specific Latent Heat of Vaporization, Evaporation of Liquids (Nature of Liquid, Temperature of Liquid, Temperature of surrounding, Presence of water vapor in Air, Area of the exposed surface of the liquid, Movement of Air, Dryness of Air, Air Pressure on the Surface of the Liquid), Evaporation causes Cooling, Evaporation vs Boiling, Applications of Cooling by Evaporation (Cooling by Fans, Fever Control, Refrigerator).

Table of Content
  1. Class 9 Physics Chapter 8 Notes
    1. Thermal Properties of Matter Notes
    2. Class 9 Physics Chapter 8 SLO Notes
  2. Class 9 Physics Chapter 8 MCQs
    1. Thermal Properties of Matter
      1. Introduction
    2. Temperature
      1. Internal Kinetic Energy
    3. Heat
    4. Measurement of Temperature
      1. Thermometry
      2. Thermometric Property
    5. Temperature Scales
      1. Centigrade or Celsius Scale
      2. Fahrenheit Scale
      3. Kelvin or Absolute Scale
    6. Relationship between Different Scales of Temperature.
    7. Thermal Expansion
    8. Thermal Expansion of Solids
      1. Linear Thermal Expansion of Solids
      2. Superficial Thermal Expansion
      3. Volume (Cubical) Thermal Expansion of Solids
    9. Thermal Expansion of Liquids
      1. Real Expansion of Liquids
      2. Apparent Expansion of Liquids
      3. Anomalous Expansion of Water
    10. Applications and Consequences of Thermal Expansion
      1. Railway lines
      2. Opening of Tight Jar Lid
      3. Transmission Lines
      4. Bimetallic Strip
    11. Heat Capacity and Specific Heat Capacity
      1. Heat Capacity (Thermal Capacity)
      2. Specific Heat Capacity (Specific Heat)
    12. Latent Heat and Phase Change
    13. Latent Heat of Fusion
    14. Specific Latent Heat of Fusion
    15. Latent Heat of Vaporization
    16. Specific Latent Heat of Vaporization
    17. Evaporation of Liquids
    18. Evaporation causes Cooling
    19. Applications of Cooling by Evaporation
      1. Cooling by Fans
      2. Fever Control
      3. Refrigerator
  3. Physics Class 9 MCQs (All Chapters)

Class 9 Physics Chapter 8 Notes

Thermal Properties of Matter Notes

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Class 9 Physics Chapter 8 Notes

Download Chapter 8 Notes

Class 9 Physics Chapter 8 SLO Notes

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Class 9 Physics Chapter 8 SLO Notes

Download Chapter 8 SLO Notes

Class 9 Physics Chapter 8 MCQs

Thermal Properties of Matter

Introduction

1 The study of heat transformations into other forms of energy is,
(a) Thermodynamics
(b) Kinematics
(c) Mechanic
(d) Dynamic
Show Answer

Thermodynamics


2 When did the study of thermodynamics begin?
(a) 18th century
(b) 19th century
(c) 20th century
(d) 21st century
Show Answer

18th century


3 What were the initial applications of steam engines during the Industrial Revolution?
(a) Powering smartphones
(b) Powering trains, factories, and water pumps
(c) Generating electricity
(d) Fueling automobiles
Show Answer

Powering trains, factories, and water pumps


4 When were the concepts of thermodynamics linked to the motions of atoms and molecules?
(a) Around 1700
(b) Around 1800
(c) Around 1900
(d) Around 2000
Show Answer

Around 1900

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Temperature

Internal Kinetic Energy

5 The measure of the degree of hotness or coldness of a body with respect to some standard is called,
(a) Temperature
(b) Heat
(c) Energy
(d) Momentum
Show Answer

Temperature


6 What is the average kinetic energy of molecules in a body related to?
(a) The color of the body
(b) The body’s weight
(c) The body’s volume
(d) The body’s temperature
Show Answer

The body’s temperature


7 What is the symbol used to represent temperature?
(a) T
(b) C
(c) F
(d) K
Show Answer

T


8 In which units is temperature commonly measured?
(a) A, B, C
(b) {}^oC, {}^oF, K
(c) X, Y, Z
(d) M, N, O
Show Answer

{}^oC, {}^oF, K


9 What is the SI unit of temperature?
(a) Celsius ({}^oC)
(b) Kelvin (K)
(c) Fahrenheit ({}^oF)
(d) All of these
Show Answer

Kelvin (K)


10 Which location is the hottest place on Earth?
(a) The Antarctic
(b) Death Valley, California
(c) The Sahara Desert
(d) The Amazon Rainforest
Show Answer

Death Valley, California


11 What is internal energy in a substance primarily composed of?
(a) Potential energy
(b) Vibrational kinetic energy
(c) Rotational kinetic energy
(d) Both kinetic and potential energies
Show Answer

Both kinetic and potential energies


12 In a solid, how do atoms primarily move?
(a) Randomly colliding with each other
(b) By stretching and contracting
(c) By jiggling in place
(d) By spinning rapidly
Show Answer

By jiggling in place


13 Which type of kinetic energy is observed in a monoatomic gas at high temperatures?
(a) Translational kinetic energy
(b) Vibrational kinetic energy
(c) Rotational kinetic energy
(d) All of these
Show Answer

Translational kinetic energy


14 In gases made up of molecules with more than one atom, what types of kinetic energy can these molecules possess?
(a) Only translational kinetic energy
(b) Translational and rotational kinetic energy
(c) Translational and vibrational kinetic energy
(d) Translational, rotational, and vibrational kinetic energy
Show Answer

Translational, rotational, and vibrational kinetic energy


15 What happens to the temperature of a gas when energy is added to it?
(a) The temperature decreases
(b) The temperature remains constant
(c) The temperature increases
(d) The temperature fluctuates
Show Answer

The temperature increases


16 What happens to the kinetic energy of molecules in a gas made up of more than one atom at high temperatures?
(a) It decreases
(b) It remains constant
(c) It increases
(d) It varies randomly
Show Answer

It increases


17 In a liquid, where are molecules primarily confined to moving?
(a) In a straight line
(b) Randomly throughout the entire volume
(c) Within the confines of the liquid’s surface
(d) In a circular pattern
Show Answer

Within the confines of the liquid’s surface


18 What type of energy is stored in liquid molecules as they approach each other due to attraction?
(a) Kinetic energy
(b) Potential energy
(c) Vibrational energy
(d) Rotational energy
Show Answer

Potential energy

Heat

19 The transfer of thermal energy from a hotter body to a colder body is called,
(a) Heat
(b) Temperature
(c) Volume
(d) Energy
Show Answer

Heat


20 What symbol is commonly used to represent heat?
(a) H
(b) E
(c) Q
(d) T
Show Answer

Q


21 What SI unit is used to measure heat?
(a) Kelvin (K)
(b) Joule (J)
(c) Celsius ({}^oC)
(d) Watt (W)
Show Answer

Joule (J)


22 When two objects with different temperatures are placed in thermal contact, what happens to their temperatures over time?
(a) Both temperatures remain the same
(b) The temperature of the hotter object decreases, while the temperature of the cooler object increases
(c) The temperature of both objects increases
(d) The temperature of both objects decreases
Show Answer

The temperature of the hotter object decreases, while the temperature of the cooler object increases


23 The state when two objects have the same temperature is said to be:
(a) Thermal equilibrium
(b) Heat transfer
(c) Thermodynamic equilibrium
(d) Temperature balance
Show Answer

Thermal equilibrium


24 When does thermal equilibrium occur between two objects initially at different temperatures?
(a) When they have equal masses
(b) When they are made of the same material
(c) After some time when they reach a common temperature
(d) When one object absorbs all the heat from the other
Show Answer

After some time when they reach a common temperature


25 In thermal equilibrium, what can be said about the flow of heat between two objects?
(a) Heat flows from the hotter object to the cooler object
(b) Heat flows from the cooler object to the hotter object
(c) Heat stops flowing between the objects
(d) Heat flows randomly between the objects
Show Answer

Heat stops flowing between the objects

Measurement of Temperature

Thermometry

26 What is the range of temperatures that our hand can bear for sensing hotness or coldness?
(a) A very large range of temperatures
(b) A very small range of temperatures
(c) The same range as a thermometer
(d) All of these
Show Answer

A very small range of temperatures


27 What is the branch of physics that deals with the measurement of temperature?
(a) Thermodynamics
(b) Heat transfer
(c) Thermometry
(d) Kinetics
Show Answer

Thermometry


28 What is an instrument called that is used to measure temperature accurately?
(a) Temperature gauge
(b) Heat sensor
(c) Thermometer
(d) Temperature meter
Show Answer

Thermometer

Thermometric Property

29 What is the term for a property that increases or decreases uniformly with changes in temperature?
(a) Variable property
(b) Temperature-independent property
(c) Thermometric property
(d) Invariant property
Show Answer

Thermometric property


30 Which of the following is NOT an example of a thermometric property?
(a) Volume of a liquid
(b) Length of a solid
(c) Gas pressure
(d) Color of a substance
Show Answer

Color of a substance


31 What is the most commonly used thermometric property?
(a) Electrical resistance
(b) Gas pressure
(c) Thermal expansion of materials
(d) Electromotive force
Show Answer

Thermal expansion of materials


32 How does a liquid in a glass thermometer measure temperature?
(a) By changes in color of the liquid
(b) By changes in the state of the liquid
(c) By variations in the volume of the liquid
(d) By variations in the pressure of the liquid
Show Answer

By variations in the volume of the liquid


33 Which liquids are commonly used in glass thermometers?
(a) Water and oil
(b) Mercury and alcohol
(c) Gasoline and acetone
(d) Sodium and potassium
Show Answer

Mercury and alcohol

Temperature Scales

34 What is a temperature scale or thermometric scale?
(a) A scale used for measuring length
(b) A scale used for measuring time
(c) A scale used for measuring temperature
(d) A scale used for measuring weight
Show Answer

A scale used for measuring temperature


35 What is another term for a temperature scale?
(a) Measurement scale
(b) Thermodynamic scale
(c) Thermometric scale
(d) Metric scale
Show Answer

Thermometric scale


36 What are the two reference points on a temperature scale called?
(a) Fixed points
(b) Temperature points
(c) Arbitrary points
(d) Measuring points
Show Answer

Fixed points


37 How many scales of temperature are commonly used?
(a) One
(b) Two
(c) Three
(d) Four
Show Answer

Three

Centigrade or Celsius Scale

38 Who introduced the Celsius scale of temperature?
(a) Daniel Gabriel Fahrenheit
(b) Anders Celsius
(c) William Thomson
(d) Lord Kelvin
Show Answer

Anders Celsius


39 What is the other name of the Celsius scale?
(a) Centigrade scale
(b) Fahrenheit scale
(c) Kelvin scale
(d) None of these
Show Answer

Centigrade scale


40 In the Celsius scale, what are the numerical values assigned to the ice point?
(a) 0{}^o C
(b) 32 {}^oC
(c) -273 {}^oC
(d) 100 {}^oC
Show Answer

0 {}^oC


41 In the Celsius scale, what are the numerical values assigned to the stream point?
(a) 0 {}^oC
(b) 32 {}^oC
(c) -273 {}^oC
(d) 100 {}^oC
Show Answer

100 {}^oC


42 What is the interval between the fixed points on the Celsius scale divided into?
(a) 360 equal divisions
(b) 100 equal divisions
(c) 180 equal divisions
(d) 212 equal divisions
Show Answer

100 equal divisions


43 Each division of the Celsius scale is called:
(a) A degree Fahrenheit
(b) A degree centigrade
(c) A Kelvin
(d) All of these
Show Answer

A degree centigrade


44 Each division on the Celsius scale is denoted by:
(a) {}^oC
(b) {}^oF
(c) K
(d) {}^oR
Show Answer

{}^oC

Fahrenheit Scale

45 Who introduced the Fahrenheit scale of temperature?
(a) Anders Celsius
(b) Daniel Gabriel Fahrenheit
(c) William Thomson
(d) Lord Kelvin
Show Answer

Daniel Gabriel Fahrenheit


46 What is the numerical value assigned to the ice point on the Fahrenheit scale?
(a) 0 {}^oF
(b) 32 {}^oF
(c) -273 {}^oF
(d) 100 {}^oF
Show Answer

32 {}^oF


47 What is the numerical value assigned to the steam point on the Fahrenheit scale?
(a) 0 {}^oF
(b) 32 {}^oF
(c) -273 {}^oF
(d) 212 {}^oF
Show Answer

212 {}^oF


48 What is the interval between the fixed points on the Fahrenheit scale divided into?
(a) 360 equal divisions
(b) 100 equal divisions
(c) 180 equal divisions
(d) 212 equal divisions
Show Answer

180 equal divisions


49 Each division of the Fahrenheit scale is called:
(a) A degree Fahrenheit
(b) A degree centigrade
(c) A Kelvin
(d) None of these
Show Answer

A degree Fahrenheit


50 Each division on the Fahrenheit scale is denoted by:
(a) {}^oC
(b) {}^oF
(c) K
(d) {}^oR
Show Answer

{}^°F

Kelvin or Absolute Scale

51 Who devised the Kelvin (Absolute) scale of temperature?
(a) Daniel Gabriel Fahrenheit
(b) Anders Celsius
(c) William Thomson (Lord Kelvin)
(d) Sir Isaac Newton
Show Answer

William Thomson (Lord Kelvin)


52 What is the other name of the Kelvin scale?
(a) Centigrade scale
(b) Fahrenheit scale
(c) Absolute scale
(d) None of these
Show Answer

Absolute scale


53 What is the numerical value assigned to the ice point on the Kelvin scale?
(a) 0 K
(b) 32 K
(c) 273 K
(d) 100 K
Show Answer

273 K


54 What is the numerical value assigned to the steam point on the Kelvin scale?
(a) 0 K
(b) 32 K
(c) -273 K
(d) 373 K
Show Answer

373 K


55 What is the interval between the fixed points on the Kelvin scale divided into?
(a) 360 equal divisions
(b) 100 equal divisions
(c) 180 equal divisions
(d) 212 equal divisions
Show Answer

100 equal divisions


56 Each division of the Kelvin scale is called:
(a) A degree Fahrenheit
(b) A degree centigrade
(c) A Kelvin
(d) All of these
Show Answer

A Kelvin


57 Each division on the Kelvin scale is denoted by:
(a) {}^oC
(b) {}^oF
(c) K
(d) {}^oR
Show Answer

K


58 What is the term for the lowest temperature at which the molecular movements of matter cease?
(a) Absolute heat point
(b) Critical temperature
(c) Absolute zero
(d) Molecular freezing point
Show Answer

Absolute zero


59 What is another term for absolute zero?
(a) Molecular standstill point
(b) Zero temperature
(c) Kelvin Zero
(d) Molecular freezing point
Show Answer

Kelvin Zero


60 What is the lowest temperature at which the molecular movements of matter cease?
(a) 0 \ {}^oC
(b) 32 \ {}^0F
(c) -273 \ {}^oC
(d) 100 \ {}^oF
Show Answer

-273°C


61 Which scale is adopted in the international system of units?
(a) Celsius (Centigrade) scale
(b) Fahrenheit scale
(c) Kelvin (Absolute) scale
(d) None of these
Show Answer

Kelvin (Absolute) scale

Relationship between Different Scales of Temperature.

62 What is the formula to convert Celsius ({}^oC) to Fahrenheit ({}^oF)?
(a) T({}^oF) = T({}^oC) + 32
(b) T({}^oF) = T({}^oC) \times \frac{9}{5} + 32

(c) T(°F) = (T({}^oC) + 32) \times \frac{9}{5}

(d) T(°F) = (T({}^oC) - 32) \times \frac{9}{5}
Show Answer

T({}^oF) = T({}^oC) \times \frac{9}{5} + 32


63 Using the general conversion formula, what is the Fahrenheit temperature equivalent of 100{}^oC ?
(a) 3 2 \ {}^oF
(b) 212 \ {}^oF
(c) 100 \ {}^oF
(d) 273 \ {}^oF
Show Answer

212 \ {}^oF


64 How do you convert Celsius (°C) to Kelvin (K) ?
(a) T(K) = T({}^oC) + 273
(b) T(K) = T({}^oC) \times \frac{9}{5} + 32
(c) T(K) = T({}^oC) – 32
(d) T(K) = T({}^oC) \times \frac{5}{9}
Show Answer

T(K) = T({}^oC) + 273


65 What is the Kelvin equivalent of 37 \ {}^oC ?
(a) 37 K
(b) 273 K
(c) 310 K
(d) 100 K
Show Answer

310 K


66 What is the formula to convert Fahrenheit ({}^oF) to Celsius ({}^oC) ?
(a) T({}^oC) = (T({}^oF) - 32) \times \frac{5}{9}
(b) T({}^oC) = T({}^oF) + 32
(c) T({}^oC) = T({}^oF) \times \frac{9}{5}
(d) T({}^oC) = T({}^oF) + 273
Show Answer

T(°C) = (T(°F) – 32) \times \frac{5}{9}


67 What is the equivalent temperature in Celsius when a thermometer reads 32 \ {}^oF ?
(a) 0 \ {}^oC
(b) 32 \ {}^oC
(c) 64 \ {}^oC
(d) -32 \ {}^oC
Show Answer

0 \ {}^oC


68 To convert Fahrenheit ({}^oF) to Kelvin (K) , you should use the formula:
(a) T(K) = (T({}^oF) - 32) \times \frac{5}{9} + 273
(b) T(K) = T({}^oF) + 32
(c) T(K) = (T({}^oF) \times \frac{5}{9}) – 273
(d) T(K) = T({}^oF) \times \frac{5}{9}
Show Answer

T(K) = (T({}^oF) - 32) \times \frac{5}{9} + 273


69 What is the equivalent temperature in Kelvin (K) when a thermometer reads 98.6 \ {}^oF ?
(a) 310.15 K
(b) 273.15 K
(c) 370.15 K
(d) 546.27 K
Show Answer

310.15 K


70 How do you convert Kelvin (K) to Celsius ({}^oC) ?
(a) T({}^oC) = T(K) – 273
(b) T({}^oC) = T(K) \times \frac{9}{5} + 32
(c) T({}^oC) = T(K) + 273
(d) T({}^oC) = T(K) \times \frac{5}{9}
Show Answer

T({}^oC) = T(K) – 273


71 If the temperature on the Kelvin scale is 310.15 \ K , what is the corresponding temperature in Celsius ({}^oC) ?
(a) 100 \ {}^oC
(b) 273.15 \ {}^oC
(c) 37 \ {}^oC
(d) 310.15 \ {}^oC
Show Answer

37 \ {}^oC


72 What is the formula to convert Kelvin (K) to Fahrenheit ({}^oF) ?
(a) T({}^oF) = T(K) – 32
(b) T({}^oF) = (T(K) - 273) \times \frac{9}{5} + 32
(c) T({}^oF) = T(K) \times \frac{5}{9}

(d) T({}^oF) = T(K) \times \frac{9}{5}
Show Answer

T({}^oF) = (T(K) - 273) \times \frac{9}{5} + 32


73 If the temperature on the Kelvin scale is 310.15 \ K , what is the corresponding temperature in Fahrenheit?
(a) 40.33 \ {}^oF
(b) 98.6 \ {}^oF
(c) 570.27 \ {}^oF
(d) 680.33 \ {}^oF
Show Answer

98.6 \ {}^oF


74 What is the freezing point of water in Kelvin (K) ?
(a) 0 K
(b) 32 K
(c) 273 K
(d) 100 K
Show Answer

273 K


75 What is the normal body temperature in degrees Celsius?
(a) 32 \ {}^oC
(b) 36 \ {}^oC
(c) 37 \ {}^oC
(d) 40 \ {}^oC
Show Answer

37 \ {}^oC

Thermal Expansion

6 What is the term used to describe the increase in size of a substance on heating?
(a) Contraction
(b) Dilution
(c) Expansion
(d) Compression
Show Answer

Expansion

Thermal Expansion of Solids

77 What are the three types of expansion a solid can undergo?
(a) Linear, circular, and volumetric
(b) Expansion in length, width and depth
(c) Expansion in length, area and volume
(d) None of these
Show Answer

Expansion in length, area and volume


78 When a solid is heated, why does it expand?
(a) The molecules move closer together
(b) The molecules vibrate through smaller distances
(c) The molecules vibrate through larger distances
(d) The molecules stop vibrating
Show Answer

The molecules vibrate through larger distances

Linear Thermal Expansion of Solids

79 What is the term used to describe the expansion in length of a substance due to a change in temperature?
(a) Superficial expansion
(b) Cubical expansion
(c) Volumetric expansion
(d) Linear expansion
Show Answer

Linear expansion


80 The value of the coefficient of linear thermal expansion depends on:
(a) The temperature change
(b) The length of the substance
(c) The type of material
(d) The pressure applied
Show Answer

The type of material


81 What is the symbol used to represent the coefficient of linear thermal expansion?
(a) \alpha
(b) \beta
(c) \gamma
(d) \delta
Show Answer

\alpha


82 What is the unit of linear thermal expansion?
(a) Meters per second (m/s)
(b) Inverse degrees Celsius or inverse Kelvin (1/{}^oC \ or \ 1/K)
(c) Newton per square meter (N/m^2)
(d) Joules per kilogram (J/kg)
Show Answer

Inverse degrees Celsius or inverse Kelvin (1/{}^oC \ or \ 1/K)


83 What is the approximate value of the coefficient of linear thermal expansion for copper?
(a) 0.1 \times 10^{-6}/{}^oC
(b) 17 \times 10^{-6}/{}^oC
(c) 10 \times 10^{-6}/{}^oC
(d) 100 \times 10^{-6}/{}^oC
Show Answer

17 \times 10^{-6}/{}^oC


84 What happens to the length of a material when it’s heated?
(a) It remains the same
(b) It decreases
(c) It increases
(d) It depends on the material
Show Answer

It increases


85 When a material undergoes linear thermal expansion, what happens to its length as the temperature rises?
(a) It decreases
(b) It remains constant
(c) It increases
(d) It oscillates
Show Answer

It increases


86 How does the change in temperature relate to the change in length in linear thermal expansion?
(a) They are unrelated
(b) Change in length is directly proportional to change in temperature
(c) Change in temperature is inversely proportional to change in length
(d) None of these
Show Answer

Change in length is directly proportional to change in temperature

Superficial Thermal Expansion

87 What is the term used to describe the increase in area of a substance due to heating?
(a) Volumetric expansion
(b) Linear expansion
(c) Superficial expansion
(d) Anomalous expansion
Show Answer

Superficial expansion

Volume (Cubical) Thermal Expansion of Solids

88 What is the increase in volume of a substance due to a rise in temperature called?
(a) Superficial expansion
(b) Linear thermal expansion
(c) Volume thermal expansion
(d) Volumetric contraction
Show Answer

Volume thermal expansion


89 Volumetric expansion is also known as:
(a) Cubical expansion
(b) Superficial expansion
(c) Linear expansion
(d) Radial expansion
Show Answer

Cubical expansion


90 What does the coefficient of volume thermal expansion (\gamma) measure?
(a) The change in length per unit length
(b) The change in area per unit area
(c) The change in volume per unit volume
(d) The change in density per unit density
Show Answer

The change in volume per unit volume


91 How is the increase in volume (\Delta V) related to the original volume (V) and the change in temperature (\Delta T) ?
(a) \Delta V \propto V \Delta T
(b) \Delta V \propto V
(c) \Delta V \propto \frac{\Delta T}{V}

(d) \Delta V \propto \frac{V}{\Delta T}
Show Answer

\Delta V \propto V \Delta T


92 What is the proportionality constant for volume thermal expansion called?
(a) \alpha
(b) \beta
(c) \gamma
(d) \delta
Show Answer

\gamma


93 In which direction do solids typically expand due to volume thermal expansion?
(a) They expand in all directions equally
(b) They expand only in the vertical direction
(c) They expand only in the horizontal direction
(d) They don’t expand in volume
Show Answer

They expand in all directions equally


94 What is the relationship between the coefficient of linear thermal expansion (\alpha) and volumetric expansion (\gamma) for solids?
(a) \alpha = \gamma
(b) \gamma = 3 \alpha
(c) \alpha = 3 \gamma
(d) \alpha = 2 \gamma
Show Answer

\gamma = 3 \alpha


95 What is the approximate value of the coefficient of volumetric expansion for copper?
(a) 0.1 \times 10^{-6}/ {}^0C
(b) 51 \times 10^{-6}/ {}^0C
(c) 10 \times 10^{-6}/ {}^0C
(d) 100 \times 10^{-6}/ {}^0C
Show Answer

51 \times 10^{-6}/ {}^0C

Thermal Expansion of Liquids

96 Which type of expansion can occur in liquids when they are heated?
(a) Linear expansion
(b) Superficial expansion
(c) Volumetric expansion
(d) All of these
Show Answer

Volumetric expansion


97 What is the increase in volume of a liquid due to heating called?
(a) Linear expansion
(b) Superficial expansion
(c) Volumetric expansion
(d) Apparent expansion
Show Answer

Volumetric expansion

Real Expansion of Liquids

98 Which type of thermal expansion in liquids is independent of the expansion of the container?
(a) Linear expansion
(b) Superficial expansion
(c) Real expansion
(d) Apparent expansion
Show Answer

Real expansion


99 What is the term used to describe the real increase in volume of a liquid per unit original volume per unit degree rise in temperature?
(a) Superficial expansion
(b) Linear expansion
(c) Coefficient of apparent expansion
(d) Coefficient of real expansion
Show Answer

Coefficient of real expansion

Apparent Expansion of Liquids

100 What is the term used to describe the apparent increase in volume of a liquid per unit original volume per unit degree rise in temperature?
(a) Superficial expansion
(b) Linear expansion
(c) Coefficient of apparent expansion
(d) Coefficient of real expansion
Show Answer

Coefficient of apparent expansion


Anomalous Expansion of Water

101 What is the term for the unusual expansion behavior of water between 0 \ {}^oC \ and \ 4 \ {}^oC ?
(a) Superficial expansion
(b) Anomalous expansion
(c) Real expansion
(d) Apparent expansion
Show Answer

Anomalous expansion


102 What is the temperature range within which water exhibits its anomalous behavior?
(a) 0 \ {}^oC \ to \ 100 \ {}^oC
(b) 0 \ {}^oC \ to \ 4 \ {}^oC
(c) 4 \ {}^oC \ to \ 100 \ {}^oC
(d) Below 0 \ {}^oC
Show Answer

0 \ {}^oC \ to \ 4 \ {}^oC


103 At which temperature does water have its maximum density?
(a) 0 \ {}^oC
(b) 4 \ {}^oC
(c) 100 \ {}^oC
(d) None \ of \ these
Show Answer

4 \ {}^oC

Applications and Consequences of Thermal Expansion

Railway lines

104 Why do railway engineers leave a small gap between two railway tracks when laying them?
(a) To save materials
(b) To make maintenance easier
(c) To prevent accidents caused by thermal expansion
(d) To reduce noise pollution
Show Answer

To prevent accidents caused by thermal expansion

Opening of Tight Jar Lid

105 How can you loosen a tight lid on a glass jar using thermal expansion?
(a) By freezing the lid
(b) By holding the lid under hot water
(c) By tapping the lid with a hammer
(d) By using a wrench
Show Answer

By holding the lid under hot water

Transmission Lines

106 Why do transmission lines sag more in the summer compared to winter?
(a) Due to the weight of the lines
(b) Due to thermal expansion of the lines
(c) Due to increased electricity demand
(d) Due to wind pressure
Show Answer

Due to thermal expansion of the lines

Bimetallic Strip

107 What is the principle behind the operation of a bimetallic strip?
(a) Equal expansion of two metals
(b) Differential expansion of two metals
(c) Magnetic attraction
(d) Optical refraction
Show Answer

Differential expansion of two metals

Heat Capacity and Specific Heat Capacity

Heat Capacity (Thermal Capacity)

108 What is the term used to describe the quantity of heat required to raise the temperature of a substance by 1 \ {}^oC \ or \ 1 K ?
(a) Heat capacity
(b) Specific heat capacity
(c) Temperature coefficient
(d) Thermal conductivity
Show Answer

Heat capacity


109 What is the mathematical expression for heat capacity (C_m) in terms of change in heat (\Delta Q) and change in temperature (\Delta T) ?
(a) C_m = \frac{\Delta Q}{\Delta T}

(b) C_m = \frac{\Delta T}{\Delta Q}
(c) C_m = \Delta Q × \Delta T
(d) C_m = \Delta Q - \Delta T
Show Answer

C_m = \frac{\Delta Q}{\Delta T}


110 Which unit is used to express heat capacity in the Standard International System?
(a) Joule per kilogram (J/kg)
(b) Joule per Kelvin (J/K)
(c) Celsius per joule ({}^oC/J)
(d) Kilogram per Kelvin (kg/K)
Show Answer

Joule per Kelvin (J/K)


111 What symbol is commonly used to represent heat capacity?
(a) Q
(b) H
(c) C_m
(d) T
Show Answer

C_m


112 Heat capacity is also known as:
(a) Thermal volume
(b) Temperature resistance
(c) Thermal inertia
(d) Thermal capacity
Show Answer

Thermal capacity

Specific Heat Capacity (Specific Heat)

113 What is the term used to describe the quantity of heat needed to raise the temperature of 1 kilogram of a substance by 1 \ {}^oC \ or \ 1 K ?
(a) Heat capacity
(b) Specific heat capacity
(c) Heat resistance
(d) Thermal conductivity
Show Answer

Specific heat capacity


114 What is the symbol used to represent specific heat capacity?
(a) Q
(b) c
(c) S
(d) H
Show Answer

c


115 Specific heat capacity is also known as:
(a) Temperature coefficient
(b) Thermal conductivity
(c) Heat capacity
(d) Specific heat
Show Answer

Specific heat


116 What is the mathematical expression for specific heat capacity (c) ?
(a) c = \frac{\Delta Q}{m \Delta T}
(b) c = m \Delta T
(c) c = \frac{Q}{m}
(d) c = \frac{T}{\Delta Q}
Show Answer

c = \frac{\Delta Q}{m \Delta T}


117 What is the unit of specific heat capacity in the International System of Units (SI)?
(a) Joules per Kelvin (J/K)
(b) Joules per kilogram per Kelvin (J/(kg.K))
(c) Kelvin per Joule (K/J)
(d) Watts per meter per Kelvin (W/(m.K))
Show Answer

Joules per kilogram per Kelvin (J/(kg.K))


118 What is the specific heat capacity of water?
(a) 100 \ J/kg.K
(b) 500 \ J/kg.K
(c) 1000 \ J/kg.K
(d) 4190 \ J/kg.K
Show Answer

4190 J/kg.K

Latent Heat and Phase Change

119 What is a phase change in a substance?
(a) A change in temperature
(b) A change in color
(c) A change in physical characteristics from one form to another
(d) A change in chemical composition
Show Answer

A change in physical characteristics from one form to another


120 When ice melts at 0 \ {}^oC , what is the temperature of the resulting water?
(a) 0 \ {}^oC
(b) 100 \ {}^oC
(c) Above 0 \ {}^oC
(d) Below 0 \ {}^oC
Show Answer

0 \ {}^oC


121 What is the term used to describe the heat required to change the physical state of a substance without changing its temperature?
(a) Thermal capacity
(b) Thermal conductivity
(c) Latent heat
(d) Specific heat
Show Answer

Latent heat


122 Latent heat is also known as:
(a) Hidden Heat
(b) Thermal Energy
(c) Sensible Heat
(d) Specific Heat
Show Answer

Hidden Heat

Latent Heat of Fusion

123 The heat energy required to melt a substance without change in temperature is called:
(a) Specific heat capacity
(b) Latent heat of fusion
(c) Thermal conductivity
(d) Heat capacity
Show Answer

Latent heat of fusion


124 What happens when liquids solidify (freeze) in terms of heat release?
(a) They release no heat
(b) They release heat equivalent to the latent heat of fusion
(c) They release heat equivalent to the specific heat
(d) They release heat equivalent to their boiling point
Show Answer

They release heat equivalent to the latent heat of fusion

Specific Latent Heat of Fusion

125 The heat energy required to change unit mass from solid to liquid without a change in temperature is called:
(a) Thermal conductivity
(b) Heat capacity
(c) Specific latent heat of fusion
(d) Latent heat of fusion
Show Answer

Specific latent heat of fusion


126 What is the formula to calculate the heat energy required for a phase change using specific latent heat of fusion (L_f) ?
(a) \Delta Q = mL_f
(b) \Delta Q = \frac{m}{\Delta T}
(c) \Delta Q = m \Delta T
(d) \Delta Q = L_f \Delta T
Show Answer

\Delta Q = mL_f


127 What is the symbol used to represent specific latent heat of fusion?
(a) L_f
(b) Q
(c) H
(d) S
Show Answer

L_f


128 What is the SI unit of specific latent heat of fusion?
(a) Joule per Kelvin (J/K)
(b) Joule per meter (J/m)
(c) Joule per kilogram (J/kg)
(d) Joule per second (J/s)
Show Answer

Joule per kilogram (J/kg)

Latent Heat of Vaporization

129 The heat energy required to transfer a substance from liquid state to gaseous state without a change in temperature is called:
(a) Specific heat capacity
(b) Latent heat of vaporization
(c) Thermal conductivity
(d) Heat capacity
Show Answer

Latent heat of vaporization

Specific Latent Heat of Vaporization

130 The heat energy required to change unit mass from liquid to gas without a change in temperature is called:
(a) Thermal conductivity
(b) Heat capacity
(c) Specific latent heat of vaporization
(d) Latent heat of fusion
Show Answer

Specific latent heat of vaporization


131 What is the formula to calculate the heat energy required for a phase change using specific latent heat of vaporization (L_v) ?
(a) \Delta Q = mL_v
(b) \Delta Q = \frac{m}{\Delta T}
(c) \Delta Q = m \Delta T
(d) \Delta Q = L_f \Delta T
Show Answer

\Delta Q = mL_v


132 What is the symbol used to represent specific latent heat of vaporization?
(a) L_v
(b) Q
(c) H
(d) S
Show Answer

L_v


133 What is the SI unit of specific latent heat of vaporization?
(a) Joule per Kelvin (J/K)
(b) Joule per meter (J/m)
(c) Joule per kilogram (J/kg)
(d) Joule per second (J/s)
Show Answer

Joule per kilogram (J/kg)


134 Which phase change involves the direct transition from a solid to a gas without passing through the liquid state?
(a) Freezing
(b) Melting
(c) Sublimation
(d) Condensation
Show Answer

Sublimation


135 The latent heat of fusion for a given substance is ___________ the latent heat of vaporization for the same substance.
(a) Greater than
(b) Less than
(c) Equal to
(d) Unrelated to
Show Answer

Greater than


136 What is the process called when a solid changes into a liquid?
(a) Sublimation
(b) Condensation
(c) Freezing
(d) Melting
Show Answer

Melting

Evaporation of Liquids

137 When a liquid changes into a gas, it is known as:
(a) Melting
(b) Freezing
(c) Evaporation
(d) Condensation
Show Answer

Evaporation


138 The process in which a gas changes into a liquid is called:
(a) Sublimation
(b) Condensation
(c) Freezing
(d) Melting
Show Answer

Condensation


139 What is the term for the change of state from a liquid to a solid?
(a) Boiling
(b) Condensation
(c) Freezing
(d) Sublimation
Show Answer

Freezing


140 Which factor affects the rate of evaporation by providing kinetic energy to liquid molecules?
(a) Nature of liquid
(b) Temperature of surrounding
(c) Temperature of the liquid
(d) Area of the exposed surface
Show Answer

Temperature of the liquid


141 In which season do wet clothes dry more slowly due to the presence of high water vapor in the air?
(a) Autumn
(b) Summer
(c) Rainy season
(d) Spring
Show Answer

Rainy season


142 Why do wet roads dry out quickly?
(a) Due to the low temperature
(b) Due to low air pressure
(c) Due to increased surface area
(d) Due to the absence of wind
Show Answer

Due to increased surface area


143 What factor affects the rate of evaporation by reducing the presence of water vapor in the air?
(a) Dryness of the air
(b) Nature of liquid
(c) Movement of air
(d) Temperature of the surrounding
Show Answer

Dryness of the air


144 On a windy day, what happens to the rate of evaporation?
(a) It decreases
(b) It remains the same
(c) It increases
(d) It depends on other factors
Show Answer

It increases


145 Which factor primarily depends on the liquid’s boiling point?
(a) Temperature of the liquid
(b) Nature of liquid
(c) Movement of air
(d) Area of the exposed surface
Show Answer

Nature of liquid


146 What role does the temperature of the surrounding play in evaporation?
(a) It has no effect on evaporation
(b) It increases the air pressure
(c) It provides kinetic energy to liquid molecules
(d) It decreases the rate of evaporation
Show Answer

It provides kinetic energy to liquid molecules


147 How does the presence of water vapor in the air affect evaporation?
(a) It increases the rate of evaporation
(b) It has no effect on evaporation
(c) It decreases the rate of evaporation
(d) It depends on the temperature
Show Answer

It decreases the rate of evaporation

Evaporation causes Cooling

148 What causes the cooling effect when a liquid evaporates?
(a) Increased kinetic energy of molecules
(b) Heat absorbed by the liquid
(c) Molecules taking heat energy with them
(d) Increased temperature of the liquid
Show Answer

Molecules taking heat energy with them


149 Which substance evaporates more quickly, water or spirit?
(a) Water
(b) Spirit
(c) They evaporate at the same rate
(d) Depends on temperature
Show Answer

Spirit


150 Why does your palm feel cold when spirit is spilled on it and quickly evaporates?
(a) The spirit is cold by nature
(b) Your palm generates cold when in contact with spirit
(c) Evaporation of spirit causes cooling
(d) The spirit takes in heat from your palm
Show Answer

Evaporation of spirit causes cooling


151 How does the cooling effect of evaporation help maintain a stable body temperature in humans?
(a) By increasing body temperature
(b) By preventing perspiration
(c) By lowering body temperature through sweat evaporation
(d) By slowing down metabolic processes
Show Answer

By lowering body temperature through sweat evaporation


152 According to the kinetic theory, what happens to the temperature of a liquid when more energetic molecules escape through evaporation?
(a) The temperature increases
(b) The temperature remains the same
(c) The temperature decreases
(d) It depends on the liquid
Show Answer

The temperature decreases


153 Which statement is true regarding the cooling effect of evaporation?
(a) Evaporation warms the surface left behind
(b) Evaporation cools the surface left behind
(c) Evaporation is unrelated to temperature changes
(d) Evaporation only occurs at high temperatures
Show Answer

Evaporation cools the surface left behind


154 Why does perspiration help cool the human body?
(a) It releases heat into the body
(b) It contains cold substances
(c) It prevents body temperature from changing
(d) It cools the body through evaporation
Show Answer

It cools the body through evaporation

Applications of Cooling by Evaporation

Cooling by Fans

155 Why do fans provide a cooling sensation in hot weather?
(a) Fans lower the room temperature
(b) Fans increase the rate of boiling
(c) Fans accelerate the rate of evaporation, which cools the body
(d) Fans increase humidity levels
Show Answer

Fans accelerate the rate of evaporation, which cools the body

Fever Control

156 How does placing a wet towel on the forehead help control fever?
(a) It lowers room temperature
(b) It absorbs heat from the environment
(c) It increases body temperature
(d) It utilizes the cooling effect of evaporation to lower the head’s temperature
Show Answer

It utilizes the cooling effect of evaporation to lower the head’s temperature

Refrigerator

157 Which part of a refrigerator is responsible for the cooling effect through evaporation?
(a) Evaporator
(b) Refrigerant
(c) Expansion valve
(d) None of these
Show Answer

Evaporator


158 What environmental concern is associated with the use of chlorofluorocarbon (CFC) chemicals as refrigerants in old refrigerators?
(a) CFCs contribute to global warming
(b) CFCs release harmful odors
(c) CFCs can damage the ozone layer
(d) CFCs are explosive
Show Answer

CFCs can damage the ozone layer


159 What is the purpose of the compressor in a refrigerator?
(a) To evaporate the refrigerant
(b) To condense the refrigerant
(c) To maintain room temperature
(d) To compress the refrigerant, raising its temperature
Show Answer

To compress the refrigerant, raising its temperature


160 What kind of refrigerant is being used in modern refrigerators to address environmental concerns?
(a) Hydro fluorocarbon (HFC)
(b) Chlorofluorocarbon (CFC)
(c) Carbon dioxide (CO_2)
(d) Methane (CH_4)
Show Answer

Hydro fluorocarbon (HFC)

Physics Class 9 MCQs (All Chapters)


Jawad Khan

Jawad Khan

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